In accordance with this recognition of the principle of the Stoics, both their logic and their morality is judged; neither the one nor the other arrives at being immanent free science. We have already remarked (p. 241) that they also occupied themselves with logical definitions, and since they made abstract thought the principle, they have brought formal logic to great perfection. Logic is hence to them logic in the sense that it expresses the activity of the understanding as of conscious understanding; it is no longer as with Aristotle, at least in regard to the categories, undecided as to whether the forms of the understanding are not at the same time the realities of things; for the forms of thought are set forth as such for themselves. Then along with this comes in, for the first time, the question respecting the harmony of thought and object or the demand that an appropriate content of thought be shown. However, since all given content may be taken into thought and posited as something thought without therefore losing its determinate character, and this determinate character contradicts and does not support the simplicity of thought, the taking of it up does not help at all; for its opposite may also be taken up and set forth as something thought. The opposition is thereby, however, only in another form; for instead of the content being in outward sensation as something not pertaining to thought and not true, as it formerly was, it now pertains to thought, but is unlike it in its determinateness, seeing that thought is the simple. Thus what was formerly excluded from the simple Notion, now comes into it again; this separation between activity of the understanding and object must indeed be made, but likewise the unity in the object as such has to be shown, if it is only something thought. Hence Scepticism cast up this opposition more especially to the Stoics, and the Stoics amongst themselves had always to improve on their conceptions. As we have just seen (p. 250) in Sextus Empiricus, they did not quite know whether they should define conception as impression or alteration, or in some other way. Now if this conception is admitted into that which directs the soul, into pure consciousness, Sextus further asks (since thought _in abstracto_ is the simple and self-identical which, as incorporeal, is neither passive nor active), How can an alteration, an impression, be made on this? Then the thought-forms are themselves incorporeal. But, according to the Stoics, only the corporeal can make an impression or bring about an alteration.[134] That is to say, on the one hand, because corporeal and incorporeal are unlike they cannot be one; and, on the other, incorporeal thought-forms, as capable of no alteration, are not the content, for this last is the corporeal only.